There's a well-known problem with managing pre-Epoch dates (Unix->1901, Windows ->1970).
There is a solution using the ADOdb Date Time Library. Refer http://wordpress.org/support/topic/27367.
The solution works (in fact it is fantastic) but it is fiddly and can be/is a dis-incentive to upgrade.
1 = Is there anything better than the ADOdb Library to deal with this problem?
2 = Is anyone interested in sharing core WP2.8 upgraded files?